The present disclosure relates generally to the field of steering wheels. More specifically, it relates to multifunction sensors on the steering wheel.
Current multifunction switches, for example steering wheel rim mounted switches, use electromechanical buttons. In most cases, each button performs a single action. Current switch configurations are generally very static, the button is visible and can be operated whether or not the function associated with the button is relevant to the current situation. Electromechanical switches generally operate based on the relative motion of two or more components, which require a gap between each of them. Such gaps can increase the risk of quality or performance issues (uneven gaps, object stuck in gaps).
Current steering wheel and driver airbag systems require physical movement of the airbag to react with a horn system. The movement requires at least 1.5-2.0 mm of travel to close a horn contact gap. This travel equates to a peripheral airbag to steering wheel gap of about 2.5 to 3.5 mm. The travel is achieved by mounting the airbag to springs and allowing the airbag to move. In addition the complex tolerancing stack between the steering wheel and airbag makes it difficult to achieving gap tolerances of less than +/−0.5 mm and symmetry tolerances between the left hand and right hand side of +/−0.3 mm. Current horn systems are also simple make/break type systems (on/off systems), with no variable output.
It would be desirable to provide a switching or sensor system for a steering wheel that has improved quality and performance. It would also be desirable to provide a horn system that is more accurately mounted and that provides variable output.